They believe Branstad wants to get rid of the Iowa Straw Poll, which has helped boost anti-establishment presidential candidates, including former Arkansas Gov. Mike Huckabee and Rep. Michele Bachmann (R-Minn.).

Conservative activists say members of Branstad’s campaign operation have tried to manipulate the rules for the upcoming Polk County GOP convention to ensure the selection of a large bloc of loyal delegates. Polk County is Iowa’s most populous county and has significant influence over the future leadership of the state party.

Branstad’s campaign initially tried to stack the process with a slate of 99 delegates, which included the governor’s family members, donors and current and former staff, according to Republicans involved in the fight over the rules. The delegates selected at the county convention will go on to serve at the district conventions later this year, which will then select the makeup of the state central committee.

These delegates could decide at the state party convention in June who runs for the open Senate and House seats being vacated due to the retirements of Sen. Tom Harkin (D-Iowa) and Rep. Tom Latham (R-Iowa).

If no candidate wins at least 35 percent of the vote in the Senate or House primary in June, the GOP state convention will choose the party’s nominee.

Conservatives worry that stacking the state and district conventions, and possibly the state central committee, with party establishment loyalists will undermine the perception of Iowa as an even playing field for presidential candidates in 2016.

“My concern is more the perception by presidential wannabes that the caucus is truly a grassroots driven process, that it’s not vulnerable to control by any one powerbroker,” said Danny Carroll, co-chairman of the Iowa Republican Party. “It needs to be fair and perceived as such in order to be meaningful.

“Establishment Republicans get nervous with candidates like Ted Cruz because they believe that kind of candidate does not play well with the independents and certainly the moderates in the party,” he added. “What they fail to appreciate is how that kind of a candidate so mobilizes the conservative base.”

Conservatives say potential outsider candidates such as Cruz, Paul, Huckabee and former Sen. Rick Santorum (R-Pa.) would all be adversely affected.

“Anybody outside of the Chris Christie, Jeb Bush, Paul Ryan triumvirate is a bad guy,” Steve Deace, an Iowa-based conservative radio host, said of the party establishment’s view of Cruz and Paul.

Deace noted that state party leaders in Michigan changed the rules for delegate apportionment after the state’s 2012 Republican primary to give Mitt Romney a larger share of the delegates.

Deace said, “I don’t think there’s any question” that part of Branstad’s motivation is to make it tougher for Cruz or Paul or another conservative firebrand to win in 2016.

“What it’s about here is control — I want to control everything even who comes out of Iowa. Absolutely,” he said.

Branstad is pushing back hard against the allegations. A spokesman for the governor said, “As in years past, the county party assembled a wide spectrum of Republican activists for consideration at the county convention. This included evangelicals, so-called moderates and everyone in between.”

“The Branstad-Reynolds Campaign continues encouraging Iowa Republicans to get involved in the caucus-to-convention process to ensure conservatives up and down the ticket are elected in November. We believe it is important to have a thriving grassroots organization heading into this November’s election and to grow the Republican Party ahead of the 2016 presidential caucuses. The only implication for 2016 is a bigger, more robust party and to suggest anything to the contrary is absurd.”

Conservative activists say Branstad’s campaign colluded with Polk County Republican Party Chairman Will Rogers to ensure that a list of 99 delegates loyal to Branstad would be cleared at the outset of the county convention. The plan was to approve the slate along with the rules of the convention, exempting them from the competition of the regular election process.

Craig Robinson, the former political director of the Republican Party of Iowa and a conservative blogger, said the Branstad campaign has tried to wrestle back control of the party using any means necessary.

“The biggest impact it’s going to have is on the leadership of the Republican Party of Iowa for the next election cycle, which includes the presidential caucus,” Robinson said in an interview. “These delegates on this at-large slate are delegates to the district and state convention, and it’s that district convention where we elect our state central committee members.”

Critics say Branstad’s campaign did not break the rules but manipulated them to dupe the attendees of the Polk County convention to approve its large slate of preferred delegates.

“They’ve incorporated this slate of at-large delegates into the rules. The first thing you do is adopt the rules. If you adopt the rules of the convention, you’re adopting the slate of 99 people,” Robinson said. “It’s very manipulative how they put this all together.

“They might not even know what they’re voting on, that there’s ramification on delegate selection,” he added.

Tea Party allies say Branstad’s political team attempted similar tactics ahead of other state county conventions.

After Republicans vented their anger over the backroom politicking, Rogers, the Polk County GOP chairman, and senior staff on Branstad’s campaign held an emergency meeting Saturday morning and discussed cutting the proposed slate of at-large delegates from 100 to 50, according to Robinson.

“I do find it troubling that campaign staff would interact with county parties as to who is and is not a delegate to district and state conventions,” said A.J. Spiker, the chairman of the Iowa Republican Party.

Spiker said the good news of the episode is that Iowa Republicans policed themselves by making it public.

“The very fact that Iowa Republicans have stood up and really fought this shows you why Iowa deserves to be first in the nation,” he said, referring to Iowa’s status as the first contest of the presidential primary season. “No matter who the campaign is, whether it’s their own governor’s campaign or a presidential campaign, if Iowa Republicans see something that’s inappropriate, they’re going to correct it.”